Protective sealing washer for storage battery



1972 H. s. ERICKSON 3,705,324

PROTECTIVE SEALING WASHER FOR STORAGE BATTERY Filed Oct. 5. 1970 INVEN TOE Ill/GO 61 ERICKSOA/ United States Patent Oifice Patented. Dec. 12, 1972 3,705,824 PROTECTIVE SEALING WASHER FOR STORAGE BATTERY Hugo S. Erickson, 915 Fowler St., Evauston, Ill. 60202 Filed Oct. 5, 1970, Ser. No. 77,872 Int. Cl. H01m 1/02 US. Cl. 136-181 2 Claims ABSTRACT OF THE DISCLOSURE The conventional lead plate storage battery in common use for starting motor car engines and similar uses is protected from corrosion where the cable is connected to the tapered lead binding post which projects above the casing of the battery. An annular washer, of rectangular cross section in a radial plane, is set over the lead terminal post and forced down into firm contact with the non-conductive plastic body of the battery casing and simultaneously into tightly compressed relationship between its inner edge and the metal of the battery post. The lower inside corner of the rectangle has a small rabbet to receive viscous oil. This prevents the acid in the battery from corroding the terminal connections.

Flexible polyethylene is one of the best materials for the washer, but conventional molding equipment cannot form the desired final shape without defects in the inner edge, and the pressure needed to force the Washer down is likely to break the washer in two.

A blank is molded, which includes the entire washer structure and additional material covering the top of the central opening. Then punching out the additional material leaves a smooth, slippery inner edge that assures easy assembly and a permanent seal that can be opened and reassembled.

In the accompanying drawings:

FIG. 1 is a fragmentary side elevation of a storage battery together with a washer 12 according to the invention and a binding post 14 projecting up through it and up through the conventional heavy clamp 16 which can be tightened by the bolt 18 and which carries a radial tube 20 through which a conductor 22 issues.

The washer 12, when in assembled position, will have the shape indicated in FIG. 3 with an outer annulus 24 of relatively greater axial dimension, and an inner annulus 26 integral with the outer annulus. The bottom of the annulus 26 is offset upwardly to leave a rabbet 28 adapted to hold viscous lubricant. When the washer is clamped in place, the bottom of this annulus 28 will be defined by the top of the battery 10 and its inner edge will be defined by the binding post 14.

A difliculty arises in practice, in that the geometrical shape of FIG. 3 cannot be formed in the conventional injection molding procedure because the material coming into the annulus will not distribute itself uniformly, and the resulting product will have cavities and irregularities that render it useless. Also the inner edge of the annulus 26 is not smooth and polished and slippery so that it can be forced down. Fingertips at opposite sides of the washer often bend the washer around a horizontal axis until it breaks into two halves.

After many failures the following procedure has been successful. A blank is first formed as in FIG. 2 with additional material in the form of a dome 30 which completes the cup shape and facilitates distribution of the filling so that a well packed cavity results. Then after that is removed from the molds, a punch 32 is thrust through to shear the central portion of the dome 30 and that is thrown away. This shearing action compacts the material along the surface where the shear has acted and gets it smoother and more uniform than it was when formed in the mold. Now when the clamp 16 is placed on top of the washer and the mechanic puts one hand on the clamp and pushes down hard while he tightens the bolt 18 with the other hand, the inner annulus 26 is unable to carry much vertical load and will flex downward a little to secure a flat surface on top. In the assembled condition of FIG. 3 all the heavy pressure of the fastened clamp reaches the battery 10 through the outer annulus 24 which has parallel faces facing in opposite direction to transmit the compression directly. But the inner annulus 26, having no such powerful support, flexes downward a little and tilts a little so that its upper edge gets a firm bearing on the binding post 14.

To install the washer, the user merely spreads a little fillet of oil in the space to be occupied by the cavity 28 and then slides the washer down over the binding post 14 until it rests in the position of FIG. 3 except that the inner annulus 26 has not been flexed downward. Excess oil is wiped off with a bit of cloth. Then when the terminal is pushed down on top, the inner annulus 26 yields a little and the heavy radial pressure that is caused by the taper of the binding post is concentrated near the upper surface of the annulus 26 where it is most effective in completing a seal.

One satisfactory plastic material for such washers is polyethylene, but it is believed there are many generally similar plastic substances that happen to go by other names, which would be suitable for the same use.

Others may readily adapt the invention for use under various conditions of service by employing one or more of the novel features disclosed, or equivalents thereof. As at present advised with respect to the apparent scope of my invention, I desire to claim the following subject matter:

1. A protective sealing washer for the tapered binding posts of electric storage batteries, consisting of an annulus bounded by surfaces of revolution; said annulus, in radial cross section, having the general shape of a compact rectangle with its longer dimension horizontal; the inner lower corner of said rectangle being recessed to define a downwardly and inwardly facing rabbet; the inner face of said annulus above said rabbet having a diameter such that it can slip down over the top of the tapered binding post and be stretched peripherally by said binding post to develop strong tension and form a tight seal where it contacts said binding post; said rectangle, in unassembled, undistorted condition having an upper surface flat and horizontal from its outer edge about half way in toward its inner edge; the remainder of said upper surface sloping upward to the inner circular face; whereby the downward pressure of the conventional electric terminal will flatten said upper surface by flexing the material above said rabbet downwardly, which tilts the inner face of said washer inwardly to concentrate the inward pressure toward the top of said inner face.

2. A Washer according to claim 1 in which the inner face of said washer has been originally molded too small and then enlarged by shearing with an axially moving punch, whereby said inner sheared face is more dense and more smooth and slippery than the molded face was before shearing.

References Cited UNITED STATES PATENTS 3,064,068 11/1962 Fouch 136-168 2,960,560 11/1960 Barke 136-181 1,680,038 8/1928 Dunzweiler 136-168 DONALD L. WALTON, Primary Examiner US. Cl. X.R.

136-135 S; 277-212 C; 339- R 

